A McIDAS-V image comparison of “before” (01 April) and “after” (22 April) Suomi NPPVIIRS 0.7 Âµm Day/Night Band data (above; courtesy of William Straka, SSEC/CIMSS) revealed the bright lights of the ongoing recovery operations associated with the sinking of the MV Sewol ferry on 16 April 2014 (Wikipedia). The bright illumination of the recovery site is located near the center of the 22 April image; the larger cluster of bright lights seen near the bottom of the 01 April image is likely a signature of extensive squid fishing operations. Numerous smaller and more dim lights from fishing boats can be seen on both images.

The ferry was taking a southbound route across the Yellow Sea, with a final destination of Jeju City (whose bright lights can be seen on the north edge of Jeju Island, at the bottom of the images).